/**
 * @PROJECT			CGI Bash Shell Interface
 * @COPYRIGHT		See COPYING in the top level directory
 * @FILE			buffer.c
 * @PURPOSE			CBSI Buffers
 * @DEVELOPERS		Nathan Angelacos <nangel@users.sourceforge.net>
 *					Rafal Kupiec <belliash@asiotec.eu.org>
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>

#include "buffer.h"

void buffer_add(buffer_t* buf, const void* data, unsigned long size) {
	unsigned long newsize;
	unsigned long index;

	if((buf->ptr + size) >= buf->limit) {
		index = (buf->limit - buf->data);
		newsize = index;
		while(newsize <= index + size) {
			newsize += 1024;
		}
		index = buf->ptr - buf->data;
		buf->data = realloc(buf->data, newsize);
		buf->limit = buf->data + newsize;
		buf->ptr = buf->data + index;
	}
	memcpy(buf->ptr, data, size);
	buf->ptr += size;
}

void buffer_destroy(buffer_t* buf) {
	if(buf->data) {
		free(buf->data);
	}
	buffer_init(buf);
}

void buffer_init(buffer_t* buf) {
	buf->data = NULL;
	buf->ptr = NULL;
	buf->limit = NULL;
}

void buffer_reset(buffer_t* buf) {
	if(buf->data) {
		buf->ptr = buf->data;
	} else {
		buf->ptr = NULL;
	}
}

void sbuffer_destroy(sbuffer_t* sbuf) {
	free(sbuf->buf);
}

int sbuffer_init(sbuffer_t* sbuf, int size) {
	sbuf->maxsize = size;
	sbuf->buf = malloc (sbuf->maxsize);
	sbuf->maxsize -= 1;
	sbuf->fh = 0;
	sbuf->eof = 0;
	sbuf->len = 0;
	sbuf->ptr = sbuf->buf;
	sbuf->bufsize = 0;
	sbuf->maxread = 0;
	sbuf->nrread = 0;
	return (sbuf->buf != NULL);
}

int sbuffer_read(sbuffer_t* sbuf, char* matchstr) {
	int len, pos;
	int r;

	if((sbuf->eof) && (sbuf->ptr > sbuf->buf)) {
		return 0;
	}
	if((sbuf->bufsize == 0) || (sbuf->ptr >= (sbuf->buf + sbuf->bufsize - strlen (matchstr)))) {
		len = sbuf->bufsize - (sbuf->ptr - sbuf->buf);
		if(len) {
			memmove(sbuf->buf, sbuf->ptr, len);
		}
		sbuf->ptr = sbuf->buf;
		sbuf->bufsize = len;
		if(fcntl(sbuf->fh, F_GETFL) == -1) {
			r = 0;
		} else {
			size_t n = sbuf->maxsize - len;
			if(sbuf->maxread && sbuf->maxread < sbuf->nrread + n) {
				n = sbuf->maxread - sbuf->nrread;
			}
			r = read(sbuf->fh, sbuf->buf + len, n);
		}
		if(r == 0 || (r < 0 && errno != EINTR)) {
			sbuf->eof = -1;
		} else {
			sbuf->bufsize += (r > 0) ? r : 0;
			sbuf->nrread += (r > 0) ? r : 0;
		}
	}
	pos = 0;
	len = sbuf->bufsize - (int) (sbuf->ptr - sbuf->buf) - strlen(matchstr);
	while(memcmp(matchstr, sbuf->ptr + pos, strlen(matchstr)) && (pos < len)) {
		pos++;
	}
	if(pos < len) {
		sbuf->len = pos;
		sbuf->segment = sbuf->ptr;
		sbuf->ptr = sbuf->segment + pos + strlen(matchstr);
		return -1;
	}
	if(sbuf->eof) {
		len += strlen(matchstr);
	}
	sbuf->segment = sbuf->ptr;
	sbuf->len = len;
	sbuf->ptr += sbuf->len;
	return (sbuf->eof) ? (-1) : (0);
}